TX2A/RX2A: UHF FM Data Transmitter and Receiver Modules
TX2A/RX2A: UHF FM Data Transmitter and Receiver Modules
TX2A/RX2A: UHF FM Data Transmitter and Receiver Modules
Tel: +44 (0) 20 8909 9595, Fax: +44 (0) 20 8909 2233, www.radiometrix.com
Features
CE certified by independent Notified Body
Verified to comply with harmonised radio standard EN 300 Fig 1: TX2A-433-64 & RX2A-433-64
220-3 and EMC standard EN 301 489-3 by accredited Test
Laboratory
Data rates up to 64 kbps
Usable range up to 300 m
Versions available on 433.92MHz and 434.42MHz
Fully screened
Available for operation at 433.92MHz or 434.42MHz in the UK and Europe, both modules combine full
screening with extensive internal filtering to ensure EMC compliance by minimising spurious radiations and
susceptibilities. The TX2A and RX2A modules will suit one-to-one and multi-node wireless links in applications
including car and building security, EPOS and inventory tracking, remote industrial process monitoring and
computer networking. Because of their small size and low power requirements, both modules are ideal for use
in portable, battery-powered applications such as hand-held terminals.
Technical Summary
Transmitter - TX2A
Crystal-locked PLL, FM modulated at up to 64 Kbps
Operation from 2.2V to 16V (Dependent on version)
+10dBm on 433.92MHz
High efficiency, >30%, DC to RF
Improved frequency and deviation accuracy
2nd harmonic, > -60dBc
Receiver - RX2A
Single conversion FM superhet
SAW front end filter gives >50dB image rejection
Operation from 2.7V to 16V @ 12mA
Built-in regulator for improved stability and supply noise rejection
-101dBm sensitivity @ 1ppm BER, 64kb/s version
-108dBm sensitivity @ 1ppm BER, 10kb/s version
RSSI output with 60dB range
Extremely low LO leakage, <-100dBm
The RX2A module is a single conversion FM superhet receiver capable of handling data rates of up to 64kbps.
It will operate from a supply of 2.7V to 16V and draws 10mA when receiving. The RX2A features a fast power-
up time for effective duty cycle power saving and a signal strength (RSSI) output with 60dB of range. Full
screening and a SAW front-end filter give good immunity to interference. The SIL style RX2A measures 48 x
17.5 x 4.5 mm excluding the pins.
TX2A transmitter
supply 5
regulator 2.2 -- 16V
4
En
433.92 MHz
2
band pass
filter buffer ÷32 φ ref
osc
35kHz
LPF
RF out VCO 7
TXD
Loop
3
Filter
RF gnd
1 6
0V
3.8 mm
32 mm
Pin description
RF GND (pins 1&3) 12.0 12.5
RF ground, internally connected to the module mm mm
Vcc (pin 5)
+2.2V to +16V DC supply. Max ripple content 0.1VP-P. Decoupling is not generally required.
0V (pin 6)
DC supply ground. Internally connected to pins 1 & 3 and module screen.
TXD (pin 7)
DC-coupled modulation input. Accepts serial digital data at 0V to 2.5V levels.
See applications notes for suggested drive methods. Input is high impedance (>100kΩ).
Notes: 1. The 3V and 5V supply variant TX2As intended for direct replacement to our SAW based TX2
modules and do not have internal regulator. They also have identical pin out as of TX2, hence lack pin
3 (GND) and pin 4 (Enable).
2. The TXD input of 3V and 5V versions require serial digital data at 0-Vcc levels. i.e. 0-3V and 0-5V
respectively
IF2/Lim 10.7MHz
IF1
LNA 1 LNA 2 10.7MHz ceramic
10.7MHz
1 discriminator
RF in
Audio LPF
(fRF - 10.7MHz)
AF 6
buffer AF out
16 CL
VCO
data 7
XTAL OSC. RT slicer RXD
CT 10kΩ
4
0V
2
RF gnd
48 mm 4.5 mm
Pin description
18.0 mm
17.5 mm
RF IN (pin 1)
50Ω input from the antenna, DC isolated
RX2A Radiometrix
RF GND (pin 2)
RF ground pin, internally connected to the PCB level
Vcc (pin 5)
+2.7V to +16.0V DC supply. Max ripple content 0.1Vp-p. Decoupling is not generally required.
AF out (pin 6)
Buffered and filtered analogue output from the FM demodulator. Standing DC bias 1.1V approx. External load
should be >10kΩ // <100pF.
RXD (pin 7)
Digital output from the internal data slicer. The data is a squared version of the signal on pin 6 (AF) and is true
data, i.e. as fed to the transmitter. Output is “open-collector” format with internal 10kΩ pull-up to Vcc (pin 5).
DC LEVELS
supply voltage 3 2.2 3.0 4.0 V -3V version
supply voltage 3 4.0 5.0 6.0 V -5V version
supply voltage 3 3 - 16 V STD
TX2A-433-64-5V
supply current @ Vcc = 5V 3 9 11 13 mA
RF power @ Vcc = 5V 2 +8 +10 +12 dBm 1
TX2A-433-64-STD
supply current @ Vcc = 5V 3 9 11 13 mA
RF power @ Vcc = 5V 2 +8 +10 +12 dBm 1
RF
nd
2 harmonic 2 - -70 -54 dBc 1
harmonics @ > 1GHz 2 - -60 -40 dBc 1
initial frequency accuracy - -20 +/-10 +20 kHz
overall frequency accuracy - -25 +/-10 +25 kHz
DC supply
Supply voltage 5 2.7 5.0 16.0 V
Supply current 5 11 11.6 13 mA 1
RF/ IF
RF sensitivity for 10dB (S+N/N) 1,6 - -115 - dBm 10kb/s version
RF sensitivity for 10dB (S+N/N) 1,6 - -108 - dBm 64kb/s version
RF sensitivity for 1ppm BER 1,7 - -108 - dBm 10kb/s version
RF sensitivity for 1ppm BER 1,7 - -101 - dBm 64kb/s version
RSSI range 1,3 - 60 - dB
IF bandwidth - - 180 - kHz
Image rejection 1 50 53 - dB
½-IF spurious rejection 1 - 94 - dB
LO leakage, conducted 1 - -120 -100 dBm
Baseband
Baseband bandwidth @ -3dB 6 0 - 7.8 kHz 10kb/s version
Baseband bandwidth @ -3dB 6 0 - 50 kHz 64kb/s version
AF level 6 - 500 - mVP-P 2
DC offset on AF out 6 0.45 1.1 1.75 V 3
Distortion on recovered AF 6 - 1 5 % 3
Ultimate (S+N)/N 6 - 40 - dB
Load capacitance, AFout/RXD 6,7 - - 100 pF
DYNAMIC TIMING
Power up with signal present
Power up to valid RSSI 3,5 - 1 - ms
Power up to stable data 5,7 - 10 30 ms 3, 10kb/s version
Power up to stable data 5,7 - 5 10 ms 3, 64kb/s version
Please note that the actual RSSI voltage at any given RF input level varies somewhat between units. The RSSI
facility is intended as a relative indicator only - it is not designed to be, or suitable as, an accurate and
repeatable measure of absolute signal level or transmitter-receiver distance.
The output on pin 3 of the module has a standing DC bias of 0.15V-0.45V (0.25V typ.) with no signal, rising to
0.9-1.3V (1.15V typ.) at maximum indication. The RSSI output source impedance is high (~50kΩ) and external
loading should therefore be kept to a minimum.
To ensure a fast response the RSSI has limited internal decoupling of 1nF to ground. This may result in a small
amount of ripple on the DC output at pin 3 of the module. If this is a problem further decoupling may be added
at the expense of response speed, in the form of a capacitor from pin 3 to ground. For example, adding 10nF
here will increase RSSI response time from 100µs to around 1ms. The value of this capacitor may be increased
without limit.
1.2
1.1
1
RSSI output (V)
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
-130 -120 -110 -100 -90 -80 -70 -60 -50
RF level (dBm)
If the connection between module and antenna does not form part of the antenna itself, it should be made using
50Ω microstrip line or coax or a combination of both. It is desirable (but not essential) to fill all unused PCB
area around the module with ground plane.
The module may be potted if required in a viscous compound which cannot enter the screen can.
C3 C4 RF
B. Loop antenna
Features A B C
helical loop whip
Ultimate performance ** * ***
Easy of design set-up ** * ***
Size *** ** *
Immunity proximity effects ** *** *
Range open ground to similar antenna 200m 100m 300m
(for TX2A-433-14-5V & RX2-433-14-5V)
Antenna selection chart
A) Helical Wire coil, connected directly to pin 2, open circuit at other end. This antenna is very
efficient given it's small size (20mm x 4mm dia.). The helical is a high Q antenna, trim the wire
length or expand the coil for optimum results. The helical de-tunes badly with proximity to other
conductive objects.
B) Loop A loop of PCB track tuned by a fixed or variable capacitor to ground at the 'hot' end and fed
from pin 2 at a point 20% from the ground end. Loops have high immunity to proximity de-
tuning.
C) Whip This is a wire, rod, PCB track or combination connected directly to pin 2 of the module.
Optimum total length is 15.5cm (1/4 wave @ 433MHz). Keep the open circuit (hot) end well
away from metal components to prevent serious de-tuning. Whips are ground plane sensitive
and will benefit from internal 1/4 wave earthed radial(s) if the product is small and plastic cased
The antenna choice and position directly controls the system range. Keep it clear of other metal in the system,
particularly the 'hot' end. The best position by far, is sticking out the top of the product. This is often not
desirable for practical/ergonomic reasons thus a compromise may need to be reached. If an internal antenna
must be used try to keep it away from other metal components, particularly large ones like transformers,
batteries and PCB tracks/earth plane. The space around the antenna is as important as the antenna itself
There is a 10% duty cycle restriction on 433.050-434.790 MHz band in most of the EU member states.
The TX2A-433 is a RF module intended to be incorporated into a wide variety of applications and finished
products, Radiometrix has no control over the end use of the TX2A-433.The harmonised band 433.050 to
434.790 MHz as detailed in Annex 1 Band E of CEPT/ERC Recommendation 70-03 (which can be
downloaded at http://www.ero.dk/scripts/docmanag98/dm.dll/QueryDoc?Cat=Recommendation)
has list of countries where Duty Cycle restriction apply.
Module users should, therefore, ensure that they comply with the stated Duty Cycle requirements of the version
of CEPT/ERC Recommendation 70-03 in place at the time of incorporation of the TX2A-433 into their product.
It should be noted that the stated Duty Cycle must not be exceeded otherwise any approval granted for the
TX2A-433 will be invalidated.
The standard frequency is 433.92MHz, for other frequency variants, please contact sales department.
Data rate: Slower version: 7.8kHz baseband B/W, data rate up to 10kb/s (suffix -10)
Faster version: 50kHz baseband B/W, data rate up to 64kb/s (suffix -64)
Evaluation platforms:
1. Universal Evaluation Kit
2. NBEK + SIL carrier
Copyright notice
This product data sheet is the original work and copyrighted property of Radiometrix Ltd. Reproduction in
whole or in part must give clear acknowledgement to the copyright owner.
Limitation of liability
The information furnished by Radiometrix Ltd is believed to be accurate and reliable. Radiometrix Ltd
reserves the right to make changes or improvements in the design, specification or manufacture of its
subassembly products without notice. Radiometrix Ltd does not assume any liability arising from the
application or use of any product or circuit described herein, nor for any infringements of patents or other
rights of third parties which may result from the use of its products. This data sheet neither states nor
implies warranty of any kind, including fitness for any particular application. These radio devices may be
subject to radio interference and may not function as intended if interference is present. We do NOT
recommend their use for life critical applications.
The Intrastat commodity code for all our modules is: 8542 6000
R&TTE Directive
After 7 April 2001 the manufacturer can only place finished product on the market under the provisions of
the R&TTE Directive. Equipment within the scope of the R&TTE Directive may demonstrate compliance
to the essential requirements specified in Article 3 of the Directive, as appropriate to the particular
equipment.
Further details are available on The Office of Communications (Ofcom) web site:
http://www.ofcom.org.uk/